Qualities of Timber Species

Learn more about the timber species that Kaltimber works with:

EUSIDEROXYLON ZWAGERIKALIMANTAN IRONWOOD

Ulin

Ulin is a remarkable wood. It's extremely slow growth rate at less than 0.5mm a year results in a highly dense wood ideal for exterior applications. Ulin is a rare tree native to Indonesia. It is threatened by habitat loss.

The government of Indonesia and the state government of Sarawak have formally banned the export of this species. Illegal smuggling continues to be a major problem. It grows in lowland primary and secondary forest up to 625m altitude. It is commonly found along rivers and adjacent hills. It requires an average annual rainfall of 2500–4000 mm.

This very important tree is one of the most durable and heaviest timbers in the world. Ulin trees can grow to attain over 1,000 years of age. Common commercially exploitable trees attain a height of 30 or more metres (100 ft) with trunk diameters of exploitable trees up to 92 cm (36 inches).

Uses: Heavy engineering, decking. Due to the excellent resistance to bacterial, fungal, insect and marine borer attack the wood is highly prized for many outdoor uses. Internationally, it is renowned for heavy construction such as a buffer between transportation trailers and heavy steel fabrications (such as boilers, pressure vessels, reactors and many others). It is also frequently found in dry docks as a timber to separate the hull of ships from the steel supporting stands.

Status: Listed as vulnerable by the IUCN (World Conservation Union). The species is threatened by over-exploitation, predominantly by illegal loggers. Current demand for the timber is fuelled for its esteem among Chinese as a coffin wood (as it is resistant to insect and rot). Included in list of vanishing timber species of the Philippines and considered almost extinct in Sabah. In Java and Sumatra it exists solely in National Parks. Currently the situation is assessed as a serious depletion of stands.

TECTONA GRANDIS

Teak

Teak is a large, deciduous tree that is dominant in mixed hardwood forests. It has small, fragrant white flowers and papery leaves that are often hairy on the lower surface. Teak timber is particularly valued for its durability and water resistance. The word teak comes from Tamil “tekku” and Malayalam word thekku. From there it went to Portuguese “teca.” Tectona grandis is found in a variety of habitats and climatic conditions from arid areas with only 500 mm of rain per year to very moist forests with up to 5,000 mm of rain per year.

Teak has been used as a boatbuilding material for over 2000 years. In addition to relatively high strength, teak is also highly resistant to rot, fungi and mildew. In addition, teak has a relatively low shrinkage ratio, which makes it excellent for applications where it undergoes periodic changes in moisture. Teak has the unusual properties of being both an excellent structural timber for framing, planking, etc., while at the same time being easily worked.

Qualities: Heartwood is dark yellow-golden, sapwood is narrow, a pale yellow-brown. Growth ring boundaries and odour distinct. Teak's natural oils make it useful in exposed locations, and make the timber termite and pest resistant. Teak is durable even when not treated with oil or varnish. Teak's high oil content, high tensile strength and tight grain makes it particularly suitable for outdoor use. Over time teak can mature to a silvery-grey finish, especially when exposed to sunlight.

Uses: Boat building, decking, all types of joinery, framing, flooring. One option is to use no finish at all, in which case the wood will naturally weather to a pleasing silver-grey. The wood may also be oiled with a finishing agent such as linseed or tung oil. This results in a pleasant, somewhat bland finish. Finally, teak may also be varnished for a deep, lustrous glow.

Density: 0.44–0.63–0.82 g/cm³

Durability: Class 2

Status: Old growth teak forests are difficult to find. Burma is the only country that still exports teak from natural forests. Indonesia has established teak plantations originally introduced by the Dutch and is the world’s second biggest teak producer.

SHOREA LAEVIFOLIA

Bengkirai

Bengkirai is a highly durable, termite resistant timber. It has straight grain and warm reddish to brown colour. It can be used in exterior or interior applications, and is suitable for flooring, decking, door and window frames, bench tops, as a structural timber and for furniture and cabinetry making.

Shorea is a genus of about 196 species of mainly rainforest trees in the family Dipterocarpaceae. The genus is named after Sir John Shore, the Governor-General of the British East India Company, 1793–1798. The tallest documented tropical angiosperm is an 88.3-metre-tall Shorea faguetiana in the Tawau Hills National Park, in Sabah on the island of Borneo.

Qualities: Heartwood basically brown to yellow to white or grey brown to green. Sapwood colour distinct from heartwood colour. The heartwood is resistant to wood-destroying fungi and termites.

Density: 0.72–0.85–0.93 g/cm³

Durability: Class 2

Uses: Heavy duty construction work, structural timbers, flooring, framing, furniture making. Highly resistant to decay when fully exposed to the weather, clear of the ground and well drained with free air circulation. Only moderately resistant to decay when used in the ground.

Status: Over 20 of the 60 species that are traded as bengkirai are listed as threatened or endangered by the IUCN (World Conservation Union).